Homogeneous distribution of fatty ester-based active cosmetic ingredients in hydrophilic thin films by means of nanodispersion

OBJECTIVE

Cosmetic films and patches are interesting forms to promote skin penetration of active ingredients as they ensure their long stay on the treated zone of the skin. Nevertheless, currently developed films and patches are most of all hydrophilic and are not adapted to the hydrophobic molecules. The aim of this study was to establish whether nanodispersion of fatty acid-based active cosmetic ingredients (ACI) could be a manner to introduce high concentrations of those ACI in hydrophilic films.

METHODS

Punica granatum seed oil hydroxyphenethyl esters (PHE) constitute a commercialized lipolytic cosmetic ingredient obtained by enzymatic conjugation of tyrosol to long-chain fatty acids and to enhance its skin diffusion. Nanodispersions of PHE were prepared by a green emulsion-solvent evaporation process and dispersed in polyvinyl alcohol films. Raman imaging coupled to multivariate analysis was used to study the distribution of PHE in the films.

RESULTS

Nanodispersions of PHE combined with antioxidant vitamin E and stabilized by Pluronic® F127 were successfully prepared. The nanodispersions show a spherical shape and a hydrodynamic diameter close to 100 nm. Raman images analysis with multivariate approaches showed a very homogeneous distribution of PHE nanodispersions in the films compared to free PHE introduced as an ethanol solution.

CONCLUSION

Nanodispersions of hydrophobic fatty acid-based ingredients seem to be relevant method to introduce this type of ingredient in hydrophilic film matrix. The co-suspension with vitamin E limits their degradation in time.

Investigating the Relationship between Antioxidants and Fatty Acid Degradation Using a Combination Approach of GC-FID and Square-Wave Voltammetry

Analytical methodology for direct investigation of antioxidant systems continues to be a pressing research area. Consumer demand for natural products requires an increase in natural antioxidants; thus, fast, high-throughput, and cost-effective screening methods are in demand. In this study, square-wave voltammetry and gas chromatography with flame ionization detection (GC-FID) were used in conjunction to monitor antioxidant and fatty acid degradation, respectively, during the accelerated degradation of an omega-3 fatty acid sample. Butylated hydroxytoluene, sesamol, and rosemary extract were investigated as antioxidants. It was determined that voltammetry could be used to monitor the reduction in oxidation current, which provides a direct assessment method for the reduction of native antioxidant concentration throughout the accelerated degradation. Furthermore, results showed that voltammetry could be used to monitor fatty acid degradation similarly to the fatty acid methyl ester analysis routinely performed using gas chromatography separation. Both voltammetry and GC-FID methods reached similar conclusions about antioxidant quality and efficiency for omega-3 fatty acid protection.